Antimony-based heterostructure varactor diode with bandgap engineered quantum well electrodes

Abstract

The present invention provides a varactor diode for frequency multipliers at submillimeter wave frequencies and above. Functionally the new diode replaces the conventional heterostructure barrier varactor diode. Two important features of the antimony-based quantum well heterostructure barrier varactor are; first: an aluminum antimnide/aluminum-arsenic-antimnide heterostructure barrier and second: a bandgap-engineered, triangular quantum well cathode and anode.

What is claimed is:  
     
       1. An antimony-based quantum heterostructure barrier varactor diode wherein the diode is comprised of five layers, where the first layer is comprised of GaInAs, the antimony based heterojunction barrier is comprised of three of the layers, with the first barrier layer comprised of AlAsSb, the second barrier layer is comprised of AlSb, and the third barrier layer is comprised of AlAsSb, and wherein the fifth layer is comprised of GaInAs“whereby the layer structure of the varactor diode is provided to maximize the variation of capacitance with voltage at high frequencies”. 
     
     
       2. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein the varactor diode is configured to improve the efficiency of a frequency multiplier so as to decrease the power loss arising during the frequency multiplication. 
     
     
       3. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein the varactor diode is optimized for application with frequency multipliers at providing outputs at submillimeter wave frequencies and above. 
     
     
       4. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein the varactor is configured to provide decreased power losses resulting from frequency multiplication and improved efficiency in frequency multiplication circuits to frequency multipliers so as to decrease the power loss that arises during frequency multiplication. 
     
     
       5. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein the antimony-based quantum well heterostructure barrier varactor diode has a reduced leakage current. 
     
     
       6. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein electron tunneling through the heterojunction barrier and thermionic emission over the top of the heterojunction barrier are reduced. 
     
     
       7. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  eherein the large barrier height of the antimony-based quantum well heterojunction barrier substantially eliminates leakage current due to electron tunneling and thermionic emission. 
     
     
       8. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein a compositionally graded triangular quantum well is provided to create a 2 dimensional electron gas at each heterointerface. 
     
     
       9. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein the confinement of the well on the anode side is detuned by an applied voltage. 
     
     
       10. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1  wherein the diode results in a more efficient varactor tripler with higher output power. 
     
     
       11. The antimony-based triangular quantum well heterostructure barrier varactor diode of  claim 1 , wherein the first layer and the fifth layer are graded proximate the heterojunction barrier to provide a pair of triangular quantum well electrodes.